diff --git a/parsedmarc/cli.py b/parsedmarc/cli.py
index c77ce36..3b31bd3 100644
--- a/parsedmarc/cli.py
+++ b/parsedmarc/cli.py
@@ -333,7 +333,7 @@ def _main():
                      mailbox_watch=False,
                      mailbox_delete=False,
                      mailbox_test=False,
-                     mailbox_batch_size=None,
+                     mailbox_batch_size=10,
                      mailbox_check_timeout=30,
                      imap_host=None,
                      imap_skip_certificate_verification=False,